Seeing the Forest for the Shrubs

Conifer forests of the interior Pacific Northwest face many threats, including intense grazing pressure by cattle, historically high densities of Rocky Mountain elk, and altered disturbance regimes (logging, insect outbreaks, and forest fires). Heavy utilization by high densities of cattle and Rocky Mountain Elk in the Pacific Northwest has altered the structure and composition of these ecosystems, resulting in the loss of shrub species. 

Not only are shrubs eliminated from the ecosystem, but wildlife is also impacted, as nesting sites, food sources, and habitat cover are lost. The objective of this work is to better understand how ungulates (cattle, elk) and disturbances (prescribed fires) affect shrub cover and high quality wildlife habitat.

This project began in 2003 and we have monitored the abundance, growth, and survival of keystone plant species (willows, aspen, cottonwoods, serviceberry, etc.) under different levels (low, moderate, high density) of cattle and elk herbivory in northeastern Oregon.

This is a collaborative project with the Pacific Northwest Research Station, Oregon State University, and the Eastern Oregon Agricultural Research Center. 

We use GPS technology to record the location of individual shrubs, and visit them 4 times per year to record their survivorship, height, size, and any reproductive activity. We then relate this to the different grazing levels of cattle and elk. This allows us to compare cattle vs. elk herbivory effects (which ungulate has the greatest impact?) as well as to compare different levels of herbivory (low, moderate, high). 

This project is a long-term experiment and is planned to last 10 years (through 2013).  This research will provide important information to land managers and allow them to make informed management decision to maintain and conserve the natural resources and biodiversity of these beautiful forest ecosystems.